Chapter 13

(1)

Case 13.1: Knee Arthrogram

Clinical Information

A 55-year-old man with knee pain and a pacemaker which precludes MRI evaluation.

Postprocessing Techniques Used and Approach

Multiplanar reconstructions, including oblique reconstructions, are viewed on the 3D workstation (Table 13.1 and Figures 13.1.1 through 13.1.3).

Diagnosis

Tear of the posterior horn of the medial meniscus with associated chon- dromalacia of the femoral and patellar cartilages.

Teaching Points

In patients who are unable to undergo MRI, noninvasive diagnosis of internal derangement of the joints is very difﬁcult. Conventional arthrography is often very limited, particularly for the knee. Many patients will therefore either forgo imaging evaluation or be referred directly to arthroscopy.

Multidetector CT arthrography now offers an excellent means of diagnosing internal derangement in patients who are unable to have MRI. The procedure is simple and highly effective. Dilute iodinated contrast is injected into the joint under ﬂuoroscopic guidance, and the patient is scanned with an isotropic acquisition. Processing is minimal, with multiplanar reconstructions adequate for most ﬁndings, although it is often helpful to review oblique reconstructions on the workstation.

Studies have shown that MDCT arthrography is highly accurate for the diagnosis of meniscal tears, assessment of unstable meniscal tears, and identiﬁcation of complete anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) tears. Sensitivity and speciﬁcity

Chapter 13

Orthopedic Imaging

238

(2)

Table 13.1. Scan Acquisition Parameters for Case 13.1, Knee Arthrogram

Slice No. and Thickness 16 ¥ 0.5mm

Coverage Through knee

Helical Pitch 0.94 : 1

Rotation Speed 0.5 sec

Dose Parameters 120 kVp, 175 mAs

Contrast Dose 20 mL intraarticular contrast mixed 50/50 with saline

A B

Figure 13.1.2. (A and B) Coronal and sagittal reconstructions though the menisci and cartilage. There are focal defects in the medial femoral cartilage and patellar cartilages (arrows).

Figure 13.1.1. Sagittal reconstruction through the medial meniscus shows a tear of the inferior surface of the posterior horn of the meniscus (arrow).

(3)

values are well over 90%. Results obtained have shown CT arthrography to perform as well as MRI for these abnormalities, but the current experience is much smaller than exists for MRI. Computed tomographic arthrography also excels at demonstration of osseous injury, osteophyte formation, and cartilage injury. Some findings that can be identified with MRI are difficult to diagnose with MDCT arthrography, including partial ACL tears, collateral ligament injury, bone contusion without fracture, and muscle or soft tissue injury.

Case 13.2: Scaphoid Fracture Nonunion

An 18-year-old man who had previously undergone surgical repair of a scaphoid fracture. He is now referred to evaluate healing and posi- tion of the pin.

Double oblique MPRs are reviewed on the workstation (Table 13.2 and Figures 13.2.1 through 13.2.3). The images are oriented along the long axis of the pin on both the oblique sagittal and oblique coronal planes.

Surface-rendered images are also used to demonstrate anatomy of the wrist.

Diagnosis

Nonunion of a scaphoid fracture following surgical pinning with avascular necrosis in the proximal pole of the scaphoid.

Figure 13.1.3. Oblique sagittal reconstruction through an intact anterior cruciate ligament (ACL).

(4)

Teaching Points

This case illustrates the advantages of using CT to follow up and evaluate patients with complex injuries. Computed tomography is superior to plain ﬁlm evaluation for demonstrating degree of healing, nonunion, and complications such as avascular necrosis. In the past, most patients with metal in place would undergo conventional tomograms for the assessment of surgical result and complications. Multi- detector CT can provide much more information in a fraction of the time it takes to perform tomograms. Magnetic resonance imaging can also be used but is often limited by artifacts from the metal. Oblique MPR images are generally most useful for demonstrating healing and bone complications such as cystic areas, erosions, and sclerosis.

Surface-rendered images are useful for demonstrating anatomy and alignment.

Table 13.2. Scan Acquisition Parameters for Case 13.2, Scaphoid Fracture Nonunion

Coverage Wrist

Contrast Dose None

Figure 13.2.1. Surface-rendered image of the wrist. Scaphoid fracture with three main fragments is present. Note the hardware cannot be seen on the surface image.

(5)

Computed tomography is also very useful for the initial diagnosis of wrist fractures. Compared to conventional radiographs, MDCT has been shown to reveal many additional occult fractures, mainly in small carpal bones. In addition, cases of suspected questionable fractures of the scaphoid or other carpal bones can be ruled out by CT. Multi- detector CT examinations are not dependent on the careful positioning of the wrist in the CT gantry. Oblique views can be generated after

A B

Figure 13.2.2. (A and B) Double oblique coronal and sagittal images oriented along the pin. The rela- tionship of the pin to the bony fragments is shown. The fracture is clearly unfused, and no signiﬁcant bony union or osseous bridging is seen.

Figure 13.2.3. Coronal oblique image ventral to the pin. The nonunion is demon- strated, but there is also sclerosis seen in the proximal fragment consistent with avascular necrosis.

(6)

the study to produce images in the proper anatomic planes. Three- dimensional reformatted images are very helpful in cases of complex trauma with multiple fractures and/or carpal dislocations.

Case 13.3: Hemophilic Arthropathy

A 40-year-old man with hemophilia B (factor IX deﬁciency) and wors- ening pain and limitation of motion in the right ankle.

Oblique multiplanar reconstructions performed on the workstation and surface-rendered images without segmentation are reviewed (Table 13.3 and Figure 13.3.1 and 13.3.2).

Diagnosis

Severe hemophilic arthropathy of the right ankle.

Teaching Points

Computed tomography is not commonly used to image arthritis in most practices, but it can be a very helpful adjunctive imaging modal- ity. Computed tomography excels in demonstrating complications of arthritis, including osteophytes, osseous loose bodies, joint narrowing, erosions, subchondral cysts, effusions, lytic areas, osteochondral defects, and occult fractures. In conjunction with arthrography it can also demonstrate cartilage loss, noncalciﬁed loose bodies, and meniscal and ligament injury.

This case illustrates the advantages of CT in this patient with hemophilia. Some of the findings shown were clearly visible on plain film radiography, but the extent of geode formation and erosive disease was significantly underestimated. Computed tomography also better demonstrates the inflammatory synovitis.

Hemophilic arthropathy is caused by repetitive bleeding into the joints. The inﬂammatory response elicited by the blood leads to synovitis, erosion, and subchondral cyst formation. Eventually, superimposed osteoarthritis occurs as the cartilage is eaten away. Repetitive hemorrhage into the bones can result in an osseous pseudotumor,

Table 13.3. Scan Acquisition Parameters for Case 13.3, Hemophilic Arthropathy

Slice No. and Thickness 16¥ 0.5mm

Coverage Both lower legs and ankles

(7)

A

C

B

Figure 13.3.1. (A–C) Multiple oblique coronal and sagittal 2-mm MPRs through the ankle. Severe subchondral cyst formation with large erosions is present within the distal tibia, talus, and calcaneus. Marked superimposed osteoarthritis is noted within the subtalar joint with joint narrowing, sclerosis, and osteophyte formation. In addition, note the hypertrophied synovium with high density from hemosiderin staining (arrows).

(8)

another signiﬁcant complication of hemophilia. The bones most frequently implicated, in order of descending frequency, are the femur, pelvis, tibia, and small bones of the hand.

Case 13.4: Aneurysmal Bone Cyst of the Mandible

A 15-year-old boy with a rapidly growing mass in the left mandible.

Curved reconstructions are performed through the mandible to gener- ate a CT Panorex type view of the mandible (Table 13.4 and Figures 13.4.1 through 13.4.3). This allows the entire mandible to be shown on one image. Surface-rendered images are used to show the bony Figure 13.3.2. Surface-rendered

image. The subtalar narrowing is seen, but most of the osseous ﬁndings are unapparent on the surface image. The high-density synovial hypertrophy is seen, however.

Table 13.4. Scan Acquisition Parameters for Case 13.4, Aneurysmal Bone Cyst of the Mandible

Coverage Face and mandible

(9)

Figure 13.4.1. Three-dimensional soft tissue volume-rendered image demonstrates a large soft tissue mass arising from the left mandible.

A B

Figure 13.4.2. (A and B) Coronal and sagittal curved planar reformatted images through the mandible show a large expansile, lytic tumor of the mandible with a very thin cortical rim that is destroyed in some regions. The matrix is heterogeneous with areas of hemorrhage and ﬂuid levels.

(10)

destruction in three dimensions. Volume rendering was also used to highlight the soft tissue mass.

Diagnosis

Aneurysmal bone cyst of the mandible.

Teaching Points

A CT examination was the ﬁrst imaging test in this patient to suggest that this lesion could possibly be an aneurysmal bone cyst. An MRI had suggested an aggressive sarcoma. The CT was also instrumental in the surgical removal and reconstruction planned for this patient. Initial biopsy result in this patient was eventually diagnosed as an aneurysmal bone cyst. However, because of the aggressive appearance on imaging, there was concern that the lesion could be arising from a preexisting, possibly malignant lesion, which was not shown on the biopsy.

Aneurysmal bone cysts are benign expansile lesions that can be clas- siﬁed as primary (65%) or secondary (35%). Secondary aneurysmal bone cysts can arise from preexisting benign or malignant lesions. Most (80%) show the radiographic characteristics of the preexisting tumor.

Many of these “blowout” lesions destroy most of the underlying process, allowing a missed diagnosis of malignancy at histologic examination. To prevent misdiagnosis, it is essential that the radiologist report any atypical and malignant features. The most common preexisting lesion is a giant cell tumor, which accounts for 19% to 39%

Figure 13.4.3. Surface-rendered view highlights the destruction of the mandibular body and ramus.

(11)

of cases in which the preceding lesion is found. Other common pre- cursor lesions include osteoblastoma, angioma, and chondroblastoma.

Less common lesions include fibrous dysplasia, nonossifying fibroma, chondromyxoid fibroma, solitary bone cyst, fibrous histiocytoma, eosinophilic granuloma, and even osteosarcoma.

The vast majority (approximately 80%) of patients with aneurysmal bone cyst are less than 20 years old. More than half of all such lesions occur in long bones, with approximately 12% to 30% of cases occurring in the spine. The pelvis accounts for approximately half of all ﬂat bone lesions. Involvement of the mandible, maxilla, and temporal bone occurs but is relatively uncommon.

Case 13.5: Congenital Scoliosis

A 12-year-old girl with congenital scoliosis. Study is performed for preoperative planning.

In addition to standard multiplanar reconstructions, curved reconstructions are performed in both sagittal and coronal planes to better demonstrate and follow the spinal curvature (Table 13.5 and Figures 13.5.1 through 13.5.3). Three-dimensional surface-rendered images are also reviewed. The ribs are removed using a 3D sculpt so that they do not obscure the spine as the image is rotated.

Diagnosis

Congenital kyphoscoliosis related to T12 hemivertebra.

Teaching Points

Patients with congenital vertebral anomalies frequently are afﬂicted with kyphoscoliosis, with the curvatures often being severe and pro- gressive. Conventional radiographic imaging for these disorders is often difﬁcult to interpret because of the patient’s small size, the com- plexity of the disorder, vertebral deformities that are not in the plane of the radiographs, and the presence of superimposed structures. It is

Table 13.5. Scan Acquisition Parameters for Case 13.5, Congenital Scoliosis

Coverage Thoracic and lumbar spine

(12)

A

C B

Figure 13.5.1. (A–C) Surface-rendered images in three projections with the ribs segmented out. Marked kyphoscoliosis is present. The cause of the scoliosis is shown to be a right T12 hemivertebra. Posterior view also demonstrates fusion of the posterior elements of the hemivertebra with those of L1, and spina biﬁda occulta of the S1 body.

(13)

Figure 13.5.3. Curved coronal reconstruction out of the plane of the hemivertebra. The spinal curvature is much easier to see on the curved image. Note the marked sclerosis and degenerative change at the T11–L1 articulation.

A B

Curved sagittal reconstructions. The ﬁrst reconstruction (A) is right parasagittal and includes the hemivertebra, while the second (B) is left parasagittal and does not include the abnormal vertebral body. The vertebral alignment and kyphosis is much easier to appreciate on the curved images compared with conventional sagittal images. On the straight sagittal images the vertebral bodies constantly move in and out of the plane and it is impossible to see more than two or three vertebra on the same image.

(14)

often difﬁcult for both the radiologist and orthopedists to formulate an accurate 3D image of the pathology from radiographic studies. Spinal fusion almost always is the treatment of choice in such patients. Accu- rate preoperative characterization of the scoliosis and anomalies is essential for successful surgery.

Multiplanar reformatted and 3D MDCT imaging offers many poten- tial advantages for defining congenital spine anomalies, including visualization of the deformity in any plane, from any angle, and with the overlying structures subtracted. Computed tomography has also been shown to be more accurate in characterizing the nature of the abnormality, and to be able to find additional abnormalities that were not detected by radiographs. A combination of 3D surface images and curved planar reconstructions are most useful for evaluation of the spine when severe kyphoscoliosis is present. The CPRs allow the spine to be viewed on one or two images rather that constantly following the spine in and out of plane on multiple images. The 3D reconstructions are valuable in defining failures of formation such as spina bifida, as well as showing the spinal curvature and alignment.

Computed tomography and MRI are often used as complementary tests for evaluation of congenital spine disorders. Magnetic resonance imaging excels in demonstrating the cord and spinal canal, whereas CT is superior for showing the vertebral bodies and for 3D reconstruction of the spine. Computed tomography also plays a major role in following these patients after spinal fusion to look at alignment and placement of hardware, and in evaluating the fusion and spinal canal.

Case 13.6: Brodie Abscess

A 22-year-old man with several months of knee pain but no systemic symptoms or fever. Plain ﬁlm showed a lytic lesion of the tibial metaphysis.

Multiplanar reconstructions are used for initial review (Table 13.6 and Figures 13.6.1 and 13.6.2). Curved planar reconstructions were also

Table 13.6. Scan Acquisition Parameters for Case 13.6, Brodie Abscess

Coverage Knee and upper calf

(15)

used to better demonstrate the tract communicating from the abscess to the cortex. Surface-rendered images were also reviewed but were not very helpful in this case.

Diagnosis

Subacute osteomyelitis of the tibial metaphysis (Brodie abscess).

Teaching Points

Brodie abscess is a form of subacute osteomyelitis. It is characterized by mild-to-moderate dull pain, intermittent symptoms, and insidious

A B

Figure 13.6.1. (A and B) Axial and sagittal 2-mm images through the proximal tibia. There is a lytic lesion in the metaphysis with a minimally sclerotic rim and small foci of sequestered bone centrally.

Thick periosteal reaction is present.

A B

Figure 13.6.2. (A and B) Axial and coronal curved planar reconstructions. The curved reconstructions are done along the length of the ﬁstula tract to better show the communication between the abscess and the bone cortex.

(16)

onset. Frequently there is a long delay between the onset of pain and diagnosis. The course is generally marked by few or no constitutional symptoms. Subacute osteomyelitis may mimic various benign and malignant conditions, resulting in delayed diagnosis and treatment.

The causative organism usually is coagulase-positive Staphylococcus (30%–60%) but also can be other gram-positive and gram-negative organisms. Lesions are most often metaphyseal but also occur in the epiphysis and diaphysis. The tibia is the most common site, but a variety of bones can be involved.

The classic radiologic ﬁnding is a lytic lesion with a sclerotic border.

Lesions can be well circumscribed or appear aggressive. Cortical hyperostosis may be present and mimic osteoid osteoma. Onionskin type periosteal reaction can also be seen. Other helpful ﬁndings include the presence of a sequestrum or a ﬁstula to the cortex or growth plate.

Computed tomography can be very useful in these patients to better characterize the lesion and look for important ancillary findings. In this case the sequestration and cortical fistula were much better seen on the CT than on plain films. The CPRs were very useful to document the communication between the abscess and the bony cortex.

Case 13.7: Radial Fracture Nonunion

A 41-year-old man status post internal ﬁxation of a radial fracture undergoing evaluation for healing and pseudoarthrosis secondary to persistent pain at the fracture site.

Oblique multiplanar reconstructions are reviewed on the workstation interactively. Surface-rendered images are also reviewed. No segmentation was needed (Table 13.7 and Figures 13.7.1 and 13.7.2).

Diagnosis

Nonunion of a mid radial shaft fracture post internal ﬁxation.

Teaching Points

One of the great advantages of current MDCT scanners is the avail- ability of reconstruction algorithms that minimize artifacts from metal.

Table 13.7. Scan Acquisition Parameters for Case 13.7, Radial Fracture Nonunion

Coverage Elbow to wrist

(17)

With previous generation scanners it was almost impossible to scan patients with signiﬁcant hardware or joint prostheses present and still obtain useful diagnostic information about the adjacent bone. Proper scan technique is important to minimize metal artifacts.

Higher kV settings (135 kV as opposed to standard 120 kV), longer rotation time (1 sec), and special reconstruction ﬁlters designed for metal artifact reduction can make a signiﬁcant difference in image quality and artifacts, although there is an increase in radiation dose to the patient.

With current MDCT scanners, we routinely scan patients with hardware in place to look for degree of healing or fusion, hardware failure, malpositioned screws, impingement on adjacent structures, or abnormalities of the underlying bone such as refracture, lytic destruction, or infection. Review of these cases on the workstation is very helpful. Interactive windowing to minimize streak artifact and use of oblique reconstructions are very helpful. Surface-rendered images are also an excellent way to demonstrate anatomy with minimal artifacts.

A B

Figure 13.7.1. (A and B) Oblique coronal and sagittal images oriented along the long axis of the radius.

There are artifacts from the metal plate; however, excellent bone detail is still present, clearly showing nonunion of the fracture despite sclerosis and thick callus.

(18)

Case 13.8: Osteochondroma of the Hand

A 23-month-old boy with swelling and reduced mobility of his second metacarpal-phalangeal (MCP) joint. A palpable hard mass is present.

Surface-rendered images of the hand and wrist are viewed in multiple projections (Table 13.8 and Figures 13.8.1 through 13.8.3). Oblique sagittal and coronal MPRs of the second digit are also performed. Segmen- tation using a 3D sculpt from the surface image is done to isolate the affected second metacarpal so it can be viewed from any angle.

Diagnosis

Osteochondroma of the second metacarpal of the hand.

Figure 13.7.2. Surface-rendered image of the forearm.

Window/level function is used to minimize streak artifact without obscuring bone detail. The nonunion is well seen with minimal artifacts.

(19)

Teaching Points

This child had a painless lump and limited motion at the second MCP joint. Computed tomography is used in this case to conﬁrm the diagnosis of osteochondroma by demonstrating contiguity of the cortex and medullary space of the bony growth with the metacarpal. The CT scan is also used for surgical planning. Excision of the osteochondroma to improve mobility was planned. The superior spatial resolution of MDCT combined with 3D imaging makes this the ideal test to characterize the lesion.

Osteochondromas are the most common benign tumors or tumorlike lesions of bone. Osteochondromas are developmental lesions rather

Table 13.8. Scan Acquisition Parameters for Case 13.8, Osteochondroma of the Hand Slice No. and Thickness 16¥ 0.5mm

Coverage Hand and wrist

Figure 13.8.1. Surface-rendered image of the hand and wrist. Osteochon- droma formation is present, involving the second metacarpal arising from the metaphysis and partially covering the epiphyseal ossiﬁcation center.

(20)

A B Figure 13.8.2. (A and B) Double oblique coronal and sagittal images show the osteochondroma arising at the metaphysis. Contiguity of the cortical and medullary space of the lesion and the metacarpal shaft is shown.

A B

Figure 13.8.3. (A and B) Segmented SR images of the isolated second metacarpal again showing the abnormality.

(21)

than true neoplasms and are often referred to as an osteocartilaginous exostosis or simply exostosis. Any bone that develops from preformed cartilage (enchondral ossiﬁcation) may develop an osteochondroma.

The long bones of the lower extremity are most frequently affected. As with other bone tumors, osteochondromas occur most often about the knee (40% of cases). The femur (usually distal) is the single most frequently affected bone (30% of cases). Tibial osteochondromas account for 15% to 20% of cases and most commonly occur in a proximal location. The humerus is also a frequent site of osteochondromas. Other more unusual locations of osteochondroma include small bones of the hands and feet, scapula, pelvis, and spine. Long bone lesions frequently affect the metaphysis, with the diaphysis being a rare location.

The radiographic appearance of osteochondromas is frequently char- acteristic. The lesion is composed of cortical and medullary bone with an overlying hyaline cartilage cap. In all cases there must be continu- ity of this lesion with the underlying native bone cortex and medullary canal. Osteochondromas may be solitary or multiple, with the latter associated with the syndrome hereditary multiple exostoses. Compli- cations are commonly associated with these exophytic masses and include cosmetic and osseous deformity, fracture, vascular compromise, neurologic sequelae, overlying bursa formation, and malignant transformation.

The vast majority of solitary osteochondromas are asymptomatic and, if detected, are found incidentally. Symptomatic lesions usually occur in younger patients, with 75% to 80% of such cases being discovered before the age of 20 years. The most common symptom related to osteochondroma is a nontender, painless cosmetic deformity related to the slowly enlargingexophytic mass. Additional complications that cause symptoms include osseous deformity, fracture, vascular compromise, neurologic sequelae, overlying bursa formation, and malignant transformation. Sur- gical intervention for these lesions may be necessary. Excision, even incomplete resection, may result in a reduction of symptoms.

Case 13.9: Posterior Labral Tear of the Shoulder

An 83-year-old woman with a prior traumatic humeral neck fracture and posterior dislocation of the shoulder. She is evaluated for persistent shoulder pain and limited mobility.

Multiplanar images are reconstructed on the scan console. Oblique MPRs are also reviewed on the workstation (Table 13.9 and Figures 13.9.1 and 13.9.2).

Diagnosis

Posterior labral tear with posterior/inferior glenoid rim fracture (reverse Bankart lesion) and healed fracture of the humeral head.

(22)

Table 13.9. Scan Acquisition Parameters for Case 13.9, Posterior Labral Tear of the Shoulder

Coverage Through shoulder

Contrast Dose 15 mL intraarticular contrast and 20 mL intraarticular air

A B

Figure 13.9.1. Oblique coronal MPR image. Deformity of the humeral head from the prior fracture is present. Coronal view shows posterior/inferior glenoid rim fracture and absence of inferior labrum.

Figure 13.9.2. (A and B) Axial 2-mm images at the level of the inferior glenoid. Tear and displacement of the posterior labrum are shown, as is the glenoid fracture.

(23)

Teaching Points

Reverse Bankart injuries are associated with posterior shoulder dislocations. Typical ﬁndings include posterior labral tear, posterior glenoid rim fracture, and reverse Hill-Sachs lesion of the anterior humeral head. Computed tomographic arthrography is an excellent way to visualize these abnormalities, particularly in patients who are unable to undergo MRI. In this patient intraarticular contrast followed by air was injected into the joint. The majority of the air leaked out of the joint through a capsular defect. I now prefer to inject contrast diluted 50/50 with saline rather than a mixed contrast/air injection for CT arthrography.

Selected Readings

Knee Arthrogram

1. Farber JM. CT arthrography and postoperative musculoskeletal imaging with multichannel computed tomography. Semin Musculoskelet Radiol 2004 Jun;8(2):157–166.

2. Lee W, Kim HS, Kim SJ, et al. CT arthrography and virtual arthroscopy in the diagnosis of the anterior cruciate ligament and meniscal abnormalities of the knee joint. Korean J Radiol 2004 Jan–Mar;5(1):47–54.

3. Mutschler C, Vande Berg BC, Lecouvet FE, et al. Postoperative meniscus:

assessment at dual-detector row spiral CT arthrography of the knee. Radi- ology 2003 Sep;228(3):635–641.

4. Vande Berg BC, Lecouvet FE, Poilvache P, et al. Dual-detector spiral CT arthrography of the knee: accuracy for detection of meniscal abnormalities and unstable meniscal tears. Radiology 2000;216:851–857.

5. Vande Berg BC, Lecouvet FE, Poilvache P, Dubuc JE, Maldague B, Malghem J. Anterior cruciate ligament tears and associated meniscal lesions:

assessment at dual-detector spiral CT arthrography. Radiology 2002;223:

403–409.

Scaphoid Fracture Nonunion

6. Farber JM. Imaging of the wrist with multichannel CT. Semin Muscu- loskelet Radiol 2004 Jun;8(2):167–173.

7. Kiuru MJ, Haapamaki VV, Koivikko MP, Koskinen SK. Wrist injuries: diagnosis with multidetector CT. Emerg Radiol 2004 Feb;10(4):182–185.

8. Neyman EG, Corl FS, Fishman EK. 3D-CT evaluation of metallic implants:

principles, techniques, and applications. Crit Rev Comput Tomogr 2002;

43(6):419–452.

9. Trumble T, Nyland W. Scaphoid nonunions. Pitfalls and pearls. Hand Clin 2001 Nov;17(4):611–624.

Hemophilic Arthropathy

10. Hermann G, Gilbert MS, Abdelwahab IF. Hemophilia: evaluation of musculoskeletal involvement with CT, sonography and MR imaging. Am J Roentgenol 1992;158:119–123.

11. Kerr R. Imaging of musculoskeletal complications of hemophilia. Semin Musculoskelet Radiol 2003 Jun;7(2):127–136.

(24)

12. Park SJ, Ryu KN. Hemophilic pseudotumor involving the musculoskeletal system: spectrum of radiologic ﬁndings. Am J Roentgenol 2004 Jul;183:55–61.

13. Stafford JM, James TT, Allen AM, Dixon LR. Hemophilic pseudotumor:

radiologic-pathologic correlation. Radiographics 2003;23:852–856.

Aneurysmal Bone Cyst of the Mandible

14. Asaumi J, Konouchi H, Hisatomi M, et al. MR features of aneurysmal bone cyst of the mandible and characteristics distinguishing it from other lesions. Eur J Radiol 2003 Feb;45(2):108–112.

15. DelBalso AM. Lesions of the jaws. Semin Ultrasound CT MR 1995 Dec;16(6):487–512.

16. Kransdorf MJ, Sweet DE. Aneurysmal bone cyst: concept, controversy, clinical presentation, and imaging. Am J Roentgenol 1995 Mar;164:573–580.

17. Weber AL, Bui C, Kaneda T. Malignant tumors of the mandible and maxilla.

Neuroimaging Clin N Am 2003 Aug;13(3):509–524.

18. Yoshiura K, Weber AL, Runnels S, Scrivani SJ. Cystic lesions of the mandible and maxilla. Neuroimaging Clin N Am 2003 Aug;13(3):485–494.

Congenital Scoliosis

19. Bush CH, Kalen V. Three-dimensional computed tomography in the assessment of congenital scoliosis. Skeletal Radiol 1999 Nov;28(11):632–637.

20. Kamimura M, Kinoshita T, Itoh H, et al. Preoperative CT examination for accurate and safe anterior spinal instrumentation surgery with endoscopic approach. J Spinal Disord Tech 2002 Feb;15(1):47–51.

21. Newton PO, Hahn GW, Fricka KB, Wenger DR. Utility of three-dimensional and multiplanar reformatted computed tomography for evaluation of pediatric congenital spine abnormalities. Spine 2002 Apr;27(8):844–850.

22. Sucato DJ, Kassab F, Dempsey M. Analysis of screw placement relative to the aorta and spinal canal following anterior instrumentation for thoracic idiopathic scoliosis. Spine 2004 Mar;29(5):554–559.

Brodie Abscess

23. Miller WB Jr, Murphy WA, Gilula LA. Brodie abscess: reappraisal. Radiol- ogy 1979 Jul;132(1):15–23.

24. Rasool MN. Primary subacute haematogenous osteomyelitis in children.

J Bone Joint Surg Br 2001 Jan;83(1):93–98.

Radial Fracture Nonunion

25. Buckwalter KA, Rydberg J, Kopecky KK, Crow K, Yang EL. Muscu- loskeletal imaging with multislice CT. Am J Roentgenol 2001 Apr;176:979–986.

26. Buckwalter KA, Farber JM. Application of multidetector CT in skeletal trauma. Semin Musculoskelet Radiol 2004 Jun;8(2):147–156.

27. Farber JM. CT arthrography and postoperative musculoskeletal imaging with multichannel computed tomography. Semin Musculoskelet Radiol 2004 Jun;8(2):157–166.

28. Horton KM. CT imaging of patients with metallic hardware. Crit Rev Comput Tomogr 2003;44(6):305–313.

29. Link TM, Berning W, Scherf S, et al. CT of metal implants: reduction of artifacts using an extended CT scale technique. Comput Assist Tomogr 2000 Jan–Feb;24(1):165–172.

(25)

30. Neyman EG, Corl FS, Fishman EK. 3D-CT evaluation of metallic implants:

principles, techniques, and applications. Crit Rev Comput Tomogr 2002;

43(6):419–452.

Osteochondroma of the Hand

31. Karasick D, Schweitzer ME, Eschelman DJ. Symptomatic osteochondromas: imaging features. Am J Roentgenol 1997;168:1507–1512.

32. Kobayashi H, Kotoura Y, Hosono M, et al. 3D-spiral CT of multiple exostoses. Comput Med Imaging Graph 1995;19:419–422.

33. Murphey MD, Choi JJ, Kransdorf MJ, Flemming DJ, Gannon FH. Imaging of osteochondroma: variants and complications with radiologic-pathologic correlation. Radiographics 2000 Sep–Oct;20(5):1407–1434.

Posterior Labral Tear of the Shoulder

34. Bresler F, Blum A, Braun M, et al. Assessment of the superior labrum of the shoulder joint with CT-arthrography and MR-arthrography: correlation with anatomical dissection. Surg Radiol Anat 1998;19:57–62.

35. Maeseneer MD, Roy FR, Lenchik L, et al. CT and MR arthrography of the normal and pathologic anterosuperior labrum and labral-bicipital complex.

Radiographics 2000;20:67–81.

36. Stoller DW, Tirman PF, Bredella MA, et al. Diagnostic Imaging: Orthope- dics. Salt Lake City, Utah: Amirsys; 2004.